Marrie RA, et al. - Researchers compared the incidence and prevalence of depression, anxiety disorder, bipolar disorder and schizophrenia in a population-based cohort with rheumatoid arthritis (RA) vs an age-, sex- and geographically matched cohort without RA. When compared to the matched population, the incidence and prevalence of depression, anxiety disorder, and bipolar disorder were seen to be increased in the RA population.